U.S. patent number 4,628,408 [Application Number 06/771,889] was granted by the patent office on 1986-12-09 for input device.
This patent grant is currently assigned to Alps Electric Co., Ltd.. Invention is credited to Kiyoshi Kimura.
United States Patent |
4,628,408 |
Kimura |
December 9, 1986 |
Input device
Abstract
An input device for use in a display unit such as a CRT includes
a lower electrode of an electrically conductive material and having
a plurality of apertures therein, a resilient insulating base
superimposed on the lower electrode and having a plurality of
integral dot spacers projecting through the apertures, the
resilient insulating base having recessed spaces, an upper flexible
insulating sheet disposed in confronting relation to the insulating
base with the dot spacers interposed therebetween, the upper
flexible insulating sheet supporting an upper electrode on one
surface thereof, a printed-circuit board disposed below the
insulating base, and a plurality of diodes mounted on the
printed-circuit board and accommodated in the spaces, the
printed-circuit board having an electrically conductive pattern
disposed on a lower surface thereof and connected to the diodes.
The upper insulating sheet has extensions extending around sides of
the insulating base and the printed-circuit board onto the lower
surface of the latter, the upper electrode having terminal leads
extending over the extensions and connected by a heat seal to the
electrically conductive pattern.
Inventors: |
Kimura; Kiyoshi
(Aza-Fujigasaki, JP) |
Assignee: |
Alps Electric Co., Ltd.
(JP)
|
Family
ID: |
15086701 |
Appl.
No.: |
06/771,889 |
Filed: |
September 3, 1985 |
Foreign Application Priority Data
|
|
|
|
|
Sep 3, 1984 [JP] |
|
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59-132668[U] |
|
Current U.S.
Class: |
361/742;
178/18.01; 200/512; 341/12; 341/5; 361/679.61; 361/749 |
Current CPC
Class: |
H01H
13/702 (20130101); H01H 13/785 (20130101); H01H
13/703 (20130101); H01H 2201/026 (20130101); H01H
2207/004 (20130101); H01H 2239/02 (20130101); H01H
2207/01 (20130101); H01H 2211/02 (20130101); H01H
2227/018 (20130101); H01H 2229/016 (20130101); H01H
2239/01 (20130101); H01H 2207/008 (20130101) |
Current International
Class: |
H01H
13/70 (20060101); H01H 13/702 (20060101); H01H
009/08 () |
Field of
Search: |
;361/331,380,392,395,398,417,419,420 ;200/85R,86R,159B,5A
;340/365A,365C,365VL,815.2,712,718,719 ;178/18,19,20 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tolin; G. P.
Attorney, Agent or Firm: Shoup; Guy W.
Claims
What is claimed is:
1. An input device comprising:
(a) a lower electrode of an electrically conductive material and
having a plurality of apertures therein;
(b) a resilient insulating base superimposed on said lower
electrode and having a plurality of integral dot spacers projecting
through said apertures, said resilient insulating base having
recessed spaces;
(c) an upper flexible insulating sheet disposed in confronting
relation to said insulating base with said dot spacers interposed
therebetween, said upper flexible insulating sheet supporting an
upper electrode on one surface thereof;
(d) a printed-circuit board disposed below said insulating
base;
(e) a plurality of diodes mounted on said printed-circuit board and
accommodated in said spaces, said printed-circuit board having an
electrically conductive pattern disposed on a lower surface thereof
and connected to said diodes; and
(f) said upper insulating sheet having extensions extending around
sides of said insulating base and said printed-circuit board onto
the lower surface of the latter, said upper electrode having
terminal leads extending over said extensions and connected by a
heat seal to said electrically conductive pattern.
2. An input device according to claim 1, wherein said recessed
spaces 10 are defined in peripheral sides of said insulating base,
said diodes being mounted on peripheral sides of said
printed-circuit board.
3. An input device according to claim 1, wherein said extensions
extend in X- and Y-axis directions of said upper insulating sheet.
Description
BACKGROUND OF THE INVENTION
The present invention relates to an input device for use with a
display unit such for example as a CRT (cathode-ray tube) used as a
computer terminal, and more particularly to a stylus-type input
device for detecting a position in which a panel surface is
depressed by a stylus.
There is known an input device composed of an upper electrode
disposed on a surface of an insulating sheet and a lower electrode
disposed on a surface of an insulating base, the upper and lower
electrodes being disposed in confronting relation with insulating
projections interposed therebetween. In such an input device, the
upper electrode has a plurality of terminal leads extending in X-
and Y-axis directions and connected to diodes for determining the
directions of currents flowing through the terminal leads. When a
certain voltage is applied between mutually confronting terminal
leads and a stylus is pressed against the insulating sheet at a
certain position, the upper electrode is depressed downwardly into
contact with the lower electrode. The potential in the X- and
Y-axis directions at the depressed position is then detected such
that the depressed position can be recognized as X and Y
coordinates. The diodes have conventionally been mounted on a block
board different from a printed-circuit board disposed in
confronting relation to the lower surface of the insulating base,
the diodes being connected by connectors or the like to the
printed-circuit board. Therefore, the wiring resistance between the
terminal leads and the diodes is increased, and the number of
connectors used is also increased, resulting in a greater cost.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an input device
in which the wiring resistance between terminal leads of an upper
electrode and diodes connected thereto is reduced as much as
possible and connectors or the like are dispensed with to achieve a
cost reduction.
To achieve the above object, diodes are mounted on a
printed-circuit board and accommodated in spaces defined in an
insulating base, and an insulating sheet has extensions extending
around sides of the insulating base and the printed-circuit board
onto a lower surface of the printed-circuit board. On the lower
surface of the printed-circuit board, terminal leads of an upper
electrode which extend over the extensions are connected by
heat-sealing to an electrically conductive pattern disposed on the
lower surface of the printed-circuit board for connection to the
diodes.
The above and other objects, features and advantages of the present
invention will become more apparent from the following description
when taken in conjunction with the accompanying drawings in which a
preferred embodiment of the present invention is shown by way of
illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of an input device according
to the present invention; and
FIG. 2 is an enlarged fragmentary cross-sectional view of the input
device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIGS. 1 and 2, a thin sheet 1 of corrosion-resistant
metal such as stainless steel, having a thickness of 1 mm for
example, has a plurality of small apertures 2 defined therethrough
at a pitch of 1 mm, for example, and each having a diameter of 0.3
mm, for example. The apertures 2 can be formed by a chemical
process such as etching or a mechanical process such as pressing.
An insulating base 3 is formed of a resilient insulating material
such as elastomer, by outsert molding, on the lower surface of the
thin metal sheet 1, as shown in FIG. 2, the insulating base 3
having a plurality of projections 4 extending through the apertures
2 beyond the upper surface of the thin metal sheet 1. The
projections 4 serve as dot spacers, and the portion of the thin
metal sheet 1 which is free from the dot spacers 4 serves as a
lower electrode. An upper flexible insulating sheet 5 is disposed
over the insulating base 3 with the dot spacers 4 interposed
therebetween. The insulating sheet 5 supports on its lower surface
an upper electrode 6 composed of a resistive layer and facing the
lower electrode 1 with an air gap 7 therebetween which is defined
by the dot spacers 4.
The upper insulating sheet 5 has extensions 5a extending in X- and
Y-axis directions supporting on their lower surfaces terminal leads
6a extending from the ends of the upper electrode 6 in the X- and
Y-axis directions. A printed-circuit board 8 is disposed on the
lower surface of the insulating base 3 and supports thereon a
pluraltiy of diodes 9 disposed in the X- and Y-axis directions and
connected respectively to the terminal leads 6a. The diodes 9 are
accommodated in recessed spaces 10 defined in the insulating base
3. The thickness of the insulating base 3, i.e., the spaces 10 is
selected to be greater than the height of the diodes 9 mounted on
the printed-circuit board 8. An electrically conductive pattern 11
for connection to terminals of the diodes 9 is formed on the lower
surface of the printed-circuit board 8. The extensions 5a of the
upper insulating sheet 5 extend around sides of the insulating base
3 and the printed-circuit board 8 onto the lower surface of the
latter, as shown in FIG. 2, and the terminal leads 6a are connected
by a heat seal 12 to the conductive pattern 11. The lower electrode
1 has a terminal 13 for connection to the printed-circuit board
8.
With the input device thus constructed, a prescribed voltage is
applied between the confronting terminal leads 6a in the X- and
Y-directions by passing currents between the terminal leads 6a in
the X- and Y-directions through the diodes 9 coupled to the
terminal leads 6a. When the upper insulating sheet 5 is depressed
at a position, the upper electrode 6 is lowered into contact with
the lower electrode 1. The potential at the depressed position in
the X- and Y-directions is detected by the lower electrode 1, and
the detected voltage is applied via the terminal 13 to the
printed-circuit board 1.
The input device of the above embodiment has the following
advantages:
(1) The diodes 9 are mounted in the X- and Y-directions on
peripheral sides of the printed-circuit board 8 and accommodated in
the spaces 10 defined in peripheral sides of the insulating base 3.
This arrangement dispenses with connectors and achieves a cost
reduction as compared with a conventional construction in which the
diodes 9 are mounted on a separate block plate that is connected by
connectors to the printed-circuit board 8.
(2) As shown in FIG. 2, the extensions 5a of the upper insulating
sheet 5 extend around the sides of the printed-circuit board 8 onto
the lower surface thereof, with the terminal leads 6a connected via
the heat seal to the conductive pattern 11 over a short distance
which is connected to the diodes 9. Therefore, the wiring
resistance is made smaller than would be the conventional
arrangement.
(3) Since the dot spacers 4 are formed of the resilient insulating
material, the dot spacers 4 will flex together with the upper
insulating sheet in the same direction when a pattern is drawn on
the upper insulating sheet 5 with a stylus. Therefore, the dot
spacers 4 give a cushioning action against the depression of the
stylus, which produces a smooth feel on cotact with the upper
insulating sheet 5.
(4) Inasmuch as the dot spacers 4 are resilient, they will flex
when depressed and produce no dead zone, with the result that the
resolution can be higher than the prior arrangement.
(5) As the dot spacers 4 are integrally formed with the insulating
base 3, they will not be peeled off. The resilient dot spacers 4
will flex when depressed by the stylus, and will be subjected to a
smaller wear on their tips than the conventional arrangement. When
the upper insulating sheet 5 is released of the pressure from the
stylus, the upper insulating sheet 5 will be restored to its
original shape under its own resiliency and the resiliency of the
dot spacers 4. Thus, the force with which the upper insulating
sheet 5 will not be reduced as it is repeatedly depressed.
(6) The lower electrode 1 is in the form of a thin metal sheet, and
the insulating base 3 and the dot spacers 4 are integrally formed
of a resilient insulating material by outsert molding. Accordingly,
the number of parts and manufacturing steps can be reduced to lower
the cost in manufacturing the switches.
With the present invention, as described above, any connectors
which have heretofore been required are dispensed with resulting in
a reduced cost, and the terminal leads of the upper electrode are
connected to the diodes through a minimum distance so that the
wiring resistance can be as small as possible.
Although a certain preferred embodiment has been shown and
described, it should be understood that many changes and
modifications may be made therein without departing from the scope
of the appended claims.
* * * * *